sqpt01.f - Man Page

real function sqpt01 (m, n, k, a, af, lda, tau, jpvt, work, lwork)
SQPT01

SQPT01

Purpose:

 SQPT01 tests the QR-factorization with pivoting of a matrix A.  The
 array AF contains the (possibly partial) QR-factorization of A, where
 the upper triangle of AF(1:k,1:k) is a partial triangular factor,
 the entries below the diagonal in the first k columns are the
 Householder vectors, and the rest of AF contains a partially updated
 matrix.

 This function returns ||A*P - Q*R|| / ( ||norm(A)||*eps*max(M,N) )
 where || . || is matrix one norm.

Parameters

M

          M is INTEGER
          The number of rows of the matrices A and AF.

N

          N is INTEGER
          The number of columns of the matrices A and AF.

K

          K is INTEGER
          The number of columns of AF that have been reduced
          to upper triangular form.

A

          A is REAL array, dimension (LDA, N)
          The original matrix A.

AF

          AF is REAL array, dimension (LDA,N)
          The (possibly partial) output of SGEQPF.  The upper triangle
          of AF(1:k,1:k) is a partial triangular factor, the entries
          below the diagonal in the first k columns are the Householder
          vectors, and the rest of AF contains a partially updated
          matrix.

LDA

          LDA is INTEGER
          The leading dimension of the arrays A and AF.

TAU

          TAU is REAL array, dimension (K)
          Details of the Householder transformations as returned by
          SGEQPF.

JPVT

          JPVT is INTEGER array, dimension (N)
          Pivot information as returned by SGEQPF.

WORK

          WORK is REAL array, dimension (LWORK)

LWORK

          LWORK is INTEGER
          The length of the array WORK.  LWORK >= M*N+N.

Author

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Definition at line 119 of file sqpt01.f.